Which molecule is a classic example of a high-energy phosphate donor used to power many biochemical reactions?

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Multiple Choice

Which molecule is a classic example of a high-energy phosphate donor used to power many biochemical reactions?

The idea being tested is that many cellular reactions are driven by transferring a phosphate group from a molecule with high phosphate-transfer potential. ATP serves as the classic high-energy phosphate donor because its terminal phosphate bond can be cleaved to release a large amount of free energy. This energy release happens because breaking that bond relieves electrostatic repulsion among the three negatively charged phosphates, the inorganic phosphate product is highly stabilized by resonance and hydration, and Mg2+ bound to ATP helps stabilize the transition state. As a result, ATP hydrolysis to ADP and Pi efficiently powers a wide variety of endergonic reactions, transport, and mechanical work in the cell. NADH and FADH2 are electron carriers; they donate high-energy electrons to the electron transport chain to generate a proton gradient and ultimately ATP, but they do not directly donate phosphate groups to drive phosphorylation. CoA carries acyl groups via a thioester bond, and its energy is in acyl transfer rather than phosphate transfer.

The idea being tested is that many cellular reactions are driven by transferring a phosphate group from a molecule with high phosphate-transfer potential. ATP serves as the classic high-energy phosphate donor because its terminal phosphate bond can be cleaved to release a large amount of free energy. This energy release happens because breaking that bond relieves electrostatic repulsion among the three negatively charged phosphates, the inorganic phosphate product is highly stabilized by resonance and hydration, and Mg2+ bound to ATP helps stabilize the transition state. As a result, ATP hydrolysis to ADP and Pi efficiently powers a wide variety of endergonic reactions, transport, and mechanical work in the cell.

NADH and FADH2 are electron carriers; they donate high-energy electrons to the electron transport chain to generate a proton gradient and ultimately ATP, but they do not directly donate phosphate groups to drive phosphorylation. CoA carries acyl groups via a thioester bond, and its energy is in acyl transfer rather than phosphate transfer.

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